Slow Query Log Not Logging

April 4, 2016 8.5k views
CentOS MariaDB DigitalOcean MySQL

Good afternoon,

we are trying to have access to our slow query log file at “/var/log/mysql/localhost-slow.log” but it looks like the file is empty. The “my.cnf” file says “!includedir /etc/my.cnf.d”, and inside that directory we have the following files:


Looking at the “server.cnf” file it looks like it’s set properly to write slow queries logs:

# These groups are read by MariaDB server.
# Use it for options that only the server (but not clients) should see
# See the examples of server my.cnf files in /usr/share/mysql/

# this is read by the standalone daemon and embedded servers

# this is only for the mysqld standalone daemon
slow-query-log = 1
slow-query-log-file = /var/log/mysql/localhost-slow.log
long_query_time = 1
# this is only for embedded server

# This group is only read by MariaDB-5.5 servers.
# If you use the same .cnf file for MariaDB of different versions,
# use this group for options that older servers don't understand

# These two groups are only read by MariaDB servers, not by MySQL.
# If you use the same .cnf file for MySQL and MariaDB,
# you can put MariaDB-only options here


Any idea on what could be the issue? We’ve tried to add the following:

slow-query-log = 1
slow-query-log-file = /var/log/mysql/localhost-slow.log
long_query_time = 1

directly into my.cnf and then restarting through service mysql restart but it didn’t work?

Thanks in advance for any help.

2 Answers
mkdir /var/log/mysql
touch /var/log/mysql/log-slow-queries.log
chown mysql:mysql -R /var/log/mysql

I had the same problem but after google I got the code from
It is working.

  • @sseleraci thanks for your suggestion but it looks like it’s not working…i guess is somewhat a matter of permission issues. How can I see which user is supposed to write logs?

Have you login to your server via ssh and type those commands?

1.make dir
mkdir /var/log/mysql

2.create empty file
touch /var/log/mysql/localhost-slow.log

3.set permission for user mysql
chown mysql:mysql -R /var/log/mysql

4.then restart mysql
service mysql restart

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